Loss of the pivotal connection between cell matrix adhesion sites and the cytoskeleton may lie at the heart of a number of diseases. This project is focused on elucidating the molecular mechanisms regulating this Imctional attachment in the developing mouse lens. Our central hypothesis is that focal adhesion kinase ^FAK) and related signaling molecules translate cell-matrix attachment into cytoskeletal rearrangements and a cascade of responses, including 1) cellular proliferation, differentiation and migration as well as 2) organization of the extracellular matrix into basement membranes. Study of this dynamic, bi-directional nteraction requires examination of a native, three-dimensional tissue structure. Our general strategy is to study these pathways in the mouse ocular lens, since it is surrounded by one of the thickest basement membranes in the body, undergoes a defined development, can be cultured intact, and is transparent, rendering it uniquely accessible to imaging analysis. We will use a conditional knockout approach to delete FAK, its only family member Pyk2, as well as integrin-linked kinase (ILK) from the developing mouse lens. Deletion of Pyk2 will addresses issues of functional redundancy, and deletion of ILK will further test our hypothesis by disrupting cell-matrix-cytoskeletal attachment through an alternative route, independent of FAK. We will use a combination of molecular, cellular, biochemical and structural approaches to address the following questions: Aim 1) Are FAK, Pyk2 and ILK signaling required for lens development? Does perturbation of this pathway result in lens pathology? Aim 2) Does disruption of FAK-related signaling result in specific cellular defects in lens cell migration, proliferation and/or differentiation? What signaling pathways are involved? Aim 3) How does disruption of FAK-related signaling alter how the lens capsule basement membrane is organized, synthesized and re-modeled? These proposed studies will provide mechanistic insight into the crosstalk required between cells and the extracellular matrix, and the signaling pathways involved. Importantly, these results will also provide unique insight into the mechanisms of eye development and potentially contriubte to a better understanding of blinding disorders such as microphthalmia and congenital cataracts that we predict may result from faulty cell matrix interactions during lens cell development.